Low Sperm Count: Causes, Diagnosis & Treatment
Low Sperm Count (Oligospermia): Causes, Diagnosis and Treatment
A low sperm count is one of the most common abnormalities identified during a male fertility assessment.
The medical term commonly used for a reduced sperm concentration is oligospermia.
Having a low sperm count does not necessarily mean that a man cannot father a child. The impact on fertility depends on the severity of the reduction and on other factors such as sperm motility, morphology and the fertility of the female partner.
In some men, the underlying cause can be identified and treated.
In others, fertility treatment may be recommended to improve the chances of conception.
The important first step is therefore to understand why the sperm count is low.
What Is a Low Sperm Count?
A low sperm count means that the concentration or total number of sperm in an ejaculate is below the expected reference range used by the laboratory.
The result is usually reported as the number of sperm per millilitre of semen.
However, concentration is only one part of the assessment.
A complete semen analysis also considers:
Total sperm number
Progressive motility
Total motility
Sperm morphology
Semen volume
This means that two men with the same sperm concentration may have very different fertility profiles.
What Is Oligospermia?
Oligospermia refers to a reduced sperm concentration.
The severity can vary from relatively mild abnormalities to extremely low sperm numbers.
In very severe cases, only a small number of sperm may be identified.
If no sperm are found in the ejaculate after appropriate testing, the condition is called azoospermia, which requires a different diagnostic approach.
Can a Man With a Low Sperm Count Still Have Children?
Yes.
A low sperm count does not automatically mean infertility.
Natural conception may still be possible, particularly when:
Sperm are moving normally
Morphology is relatively favourable
The female partner has no significant fertility problems
The sperm count is only mildly reduced
However, as sperm numbers become increasingly low, the probability of natural conception may decrease.
The appropriate approach depends on the complete fertility assessment rather than sperm count alone.
What Causes Low Sperm Count?
There are many potential causes of low sperm count.
These include:
Varicocele
Hormonal disorders
Genetic abnormalities
Testicular injury
Previous infection
Certain medications
Testosterone therapy
Anabolic steroid use
Heat exposure
Lifestyle factors
Obesity
Smoking
Some systemic illnesses
Unknown causes
Because the causes are so varied, treatment should be based on the underlying diagnosis.
Can Hormonal Problems Cause Low Sperm Count?
Yes.
Sperm production depends on a complex hormonal system involving:
GnRH
FSH
LH
Testosterone
If this system is disrupted, sperm production may decrease.
For example, men with hypogonadotropic hypogonadism may have low FSH and LH and significantly reduced sperm production.
In selected cases, treating the hormonal disorder can restore spermatogenesis.
Can Testosterone Cause Low Sperm Count?
Yes.
This is an especially important cause because testosterone is often mistakenly thought to improve male fertility.
External testosterone can suppress FSH and LH.
As a result, the testicles receive less stimulation and sperm production may decline significantly.
In severe cases, testosterone therapy can result in azoospermia.
Men taking testosterone who want to conceive should therefore discuss fertility-preserving options with a specialist.
Can Varicocele Cause Low Sperm Count?
Yes.
A varicocele is an enlargement of veins within the scrotum.
It is one of the recognised conditions associated with impaired male fertility.
A varicocele may affect:
Sperm concentration
Motility
Morphology
Testicular function
However, not every man with a varicocele needs treatment.
Treatment decisions depend on factors such as the clinical findings, semen analysis and fertility goals.
Can Infection Cause Low Sperm Count?
Certain infections and inflammatory conditions can affect sperm production or sperm transport.
The impact depends on:
Type of infection
Severity
Duration
Whether the testicles were involved
Whether scarring occurred
A history of significant testicular infection should therefore be discussed during fertility assessment.
Can Heat Reduce Sperm Count?
The testicles function best at a temperature slightly below core body temperature.
Significant or prolonged heat exposure may affect spermatogenesis in some men.
Potential sources can include:
Repeated hot-tub exposure
Certain occupational environments
Prolonged high-temperature exposure
However, heat is only one possible factor and should not automatically be assumed to be the cause of a low sperm count.
Can Smoking Cause Low Sperm Count?
Smoking has been associated with adverse effects on several aspects of male reproductive health.
It may affect:
Sperm concentration
Motility
Morphology
Sperm DNA integrity
Stopping smoking is therefore a reasonable step for men trying to optimise reproductive health.
Can Obesity Affect Sperm Count?
Excess body weight can be associated with hormonal changes and impaired reproductive function.
Obesity may influence:
Testosterone levels
Oestrogen metabolism
Testicular function
Sperm production
Weight management may therefore form part of a broader fertility strategy where appropriate.
Can Stress Cause Low Sperm Count?
Severe or prolonged psychological and physical stress may affect reproductive health.
Stress can influence:
Hormonal function
Sexual function
Sleep
Lifestyle behaviours
However, it is usually inappropriate to attribute a significantly abnormal semen analysis to stress alone.
A proper medical assessment is still required.
Can a Fever Temporarily Lower Sperm Count?
Yes.
A significant fever or systemic illness can temporarily affect sperm production.
This happens because spermatogenesis is sensitive to changes in the testicular environment.
The effect may not appear immediately and can persist for a period after the illness has resolved.
If a man develops an abnormal semen analysis shortly after a significant illness, repeat testing may be appropriate.
Why Should a Semen Analysis Be Repeated?
Sperm production can fluctuate.
One abnormal sample does not always represent a man's long-term fertility potential.
Repeat testing may be recommended because results can be influenced by:
Recent fever
Illness
Abstinence period
Incomplete sample collection
Medications
Laboratory variation
The need for repeat testing depends on the severity and type of abnormality.
What Tests Are Needed When Sperm Count Is Low?
The evaluation depends on the severity of the abnormality.
It may include:
Semen Analysis
Usually repeated when clinically appropriate.
Hormonal Testing
Possible tests include:
Testosterone
FSH
LH
Prolactin
Physical Examination
The specialist may assess:
Testicular size
Varicocele
Epididymis
Vas deferens
Genetic Testing
May be recommended in men with severe sperm-production abnormalities.
Imaging
Ultrasound or other imaging may be appropriate in selected cases.
When Is Genetic Testing Recommended?
Genetic testing becomes particularly important when sperm production is severely impaired.
Depending on the clinical situation, testing may include:
Karyotyping
Y-chromosome microdeletion testing
Other genetic investigations
For example, certain genetic abnormalities can cause severe oligospermia or azoospermia.
Understanding the genetic cause can influence treatment decisions and counselling regarding assisted reproduction.
What Is Severe Oligospermia?
Severe oligospermia means that the sperm concentration is markedly reduced.
The lower the sperm count, the more important it becomes to investigate the underlying cause.
Severe reductions may be associated with:
Hormonal abnormalities
Genetic conditions
Testicular dysfunction
Varicocele
Previous testicular injury
Medication or testosterone suppression
Severe oligospermia may also influence the choice between natural conception and assisted reproductive treatment.
Can Low Sperm Count Be Improved Naturally?
Sometimes lifestyle changes may support overall reproductive health.
These may include:
Stopping smoking
Maintaining a healthy weight
Limiting excessive alcohol intake
Avoiding unnecessary anabolic steroids
Managing medical conditions
Maintaining regular physical activity
Avoiding prolonged excessive heat exposure
However, lifestyle changes should not replace medical investigation when sperm counts are significantly abnormal.
If a correctable medical cause exists, treating that cause is usually more important than relying on supplements or lifestyle changes alone.
Do Fertility Supplements Increase Sperm Count?
Many supplements are marketed for male fertility.
However, evidence for individual supplements varies, and they should not be considered a substitute for diagnosing the underlying cause.
A man with severe oligospermia should not delay medical assessment simply because he is taking fertility supplements.
The priority should be identifying whether there is:
Hormonal disease
Varicocele
Genetic abnormality
Testicular dysfunction
Medication-related suppression
Another treatable cause
Can Varicocele Treatment Improve Sperm Count?
In selected men, treatment of a clinically significant varicocele may improve semen parameters.
However, treatment is not appropriate for every varicocele.
The decision is based on factors such as:
Clinical examination
Semen analysis
Symptoms
Testicular findings
Fertility goals
A specialist should determine whether intervention is likely to provide meaningful benefit.
Can Hormonal Treatment Increase Sperm Count?
It depends entirely on the hormonal diagnosis.
Men with certain forms of hormonal infertility may respond to treatment designed to restore reproductive hormone stimulation.
For example, men with hypogonadotropic hypogonadism may benefit from gonadotropin therapy.
However, giving testosterone to a man with low sperm count is not generally a fertility treatment because it can suppress spermatogenesis.
What If the Sperm Count Remains Very Low?
If the sperm count remains severely reduced despite appropriate treatment, assisted reproduction may be considered.
Depending on the sperm parameters, options may include:
IUI
IVF
ICSI
ICSI can be particularly useful when sperm numbers are very low because an individual sperm can be selected and injected directly into an egg.
The appropriate approach depends on both partners and the complete fertility assessment.
Can Sperm Retrieval Be Used With Severe Oligospermia?
In some situations, sperm retrieval may be considered, particularly when sperm are extremely rare or absent from the ejaculate.
Procedures such as surgical sperm retrieval may be appropriate depending on whether sperm production is present within the testicles.
For men with non-obstructive azoospermia, micro-TESE may be considered in selected cases.
This is different from treating uncomplicated mild oligospermia.
Low Sperm Count vs Azoospermia
These conditions should not be confused.
Low Sperm Count
Sperm are present in the ejaculate, but their concentration or total number is reduced.
Azoospermia
No sperm are detected in the ejaculate.
Azoospermia requires a more extensive investigation to determine whether the cause is:
Obstructive
Hormonal
Genetic
Testicular
The treatment pathway can therefore be very different.
Does Low Sperm Count Mean IVF Is Necessary?
Not necessarily.
Some men with low sperm counts can conceive naturally.
Others may benefit from IUI or IVF/ICSI depending on the severity of the sperm abnormality and other fertility factors.
The decision should not be based on sperm count alone.
When Should a Man With Low Sperm Count See a Specialist?
Specialist assessment is particularly important when:
The sperm count is severely reduced
The abnormality persists on repeat testing
Azoospermia is present
Testosterone is low
FSH or LH is abnormal
There is a varicocele
There is a history of testicular injury
There has been previous testosterone or anabolic steroid use
Pregnancy has not occurred despite appropriate attempts
The earlier the underlying cause is identified, the more options may be available.
How Is Low Sperm Count Treated?
Treatment depends on the cause.
Hormonal Cause
→ Treat the underlying hormonal disorder.
Testosterone Suppression
→ Stop or modify suppressive treatment under medical supervision and consider fertility-focused therapy.
Varicocele
→ Consider treatment in appropriately selected men.
Genetic Cause
→ Individualised fertility counselling and treatment.
Severe Sperm Production Failure
→ Consider assisted reproduction and, in selected cases, surgical sperm retrieval.
No Identifiable Cause
→ Lifestyle optimisation and fertility treatment may be considered according to the couple's circumstances.
Low Sperm Count: Key Takeaway
A low sperm count is a finding, not a final diagnosis.
There are many possible causes, from hormonal disorders and varicocele to genetic abnormalities, medications and testicular conditions.
Some causes are treatable, while others may require assisted reproductive techniques.
The most important step is therefore not simply trying to increase the sperm count, but understanding why it is low.
A complete assessment can help determine whether natural conception remains realistic, whether treatment may improve sperm production or whether assisted reproduction would provide the best opportunity for pregnancy.
Book a Male Fertility Consultation
If you have been told that you have a low sperm count or oligospermia, a specialist male fertility assessment can help identify the underlying cause and determine the most appropriate treatment strategy.
Book a consultation with Professor Amr Raheem to discuss your sperm count, fertility assessment and available treatment options.
References
European Society for Sexual Medicine (ESSM). 16th ESSM Congress Joint with the 12th EFS Congress – Final Programme, Istanbul, 2014. The programme contains scientific material related to male infertility and reproductive medicine. ESSM 2014 Scientific Programme
European Association of Urology (EAU). EAU Guidelines on Sexual and Reproductive Health – Male Infertility. Guidance covering the evaluation and management of abnormal semen parameters and male infertility. EAU Male Infertility Guidelines
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